RE: DLE222 Starter System - The Project
Just a bit more on gear meshing....
For anyone who is interested, the determination of the actual distant between pinion and driven gear is the pitch radius of pinion gear + pitch radius of the driven gear, not anything else. For example, a 60mm diameter gear may have it's pitch radius at 29mm, while the pinion gear of 18mm diameter may have it's pitch radius at 8mm. Therefore for this set of meshing we would have 29 + 8 = 37mm of distant center to center. The precision of this distant however lies 100% on gear cutting quality.
This pitch radius also determine the gear teeth size. The closer the pitch radius to the actual gear radius, the smaller the teeth. The smaller the teeth, the more number of teeth will be there for the same diameter gear, and off course less load carrying capability. However the smaller the teeth, the smoother the meshing is, less friction, less noise... better efficiency and everything else.
This is where a designer have to consider a lot more things before deciding on a specific gear tooth size.